Fault diagnosis of rotating machinery based on multiple ANFIS combination with GAs

This paper presents a novel method for fault diagnosis based on empirical mode decomposition (EMD), an improved distance evaluation technique and the combination of multiple adaptive neuro-fuzzy inference systems (ANFISs). The method consists of three stages. First, prior to feature extraction, some preprocessing techniques, like filtration, demodulation and EMD are performed on vibration signals to acquire more fault characteristic information. Then, six feature sets, including time- and frequency-domain statistical features of both the raw and preprocessed signals, are extracted. Second, an improved distance evaluation technique is proposed, and with it, six salient feature sets are selected from the six original feature sets, respectively. Finally, the six salient feature sets are input into the multiple ANFIS combination with genetic algorithms (GAs) to identify different abnormal cases. The proposed method is applied to the fault diagnosis of rolling element bearings, and testing results show that the multiple ANFIS combination can reliably recognise different fault categories and severities, which has a better classification performance compared to the individual classifiers based on ANFIS. Moreover, the effectiveness of the proposed feature selection method based on the improved distance evaluation technique is also demonstrated by the testing results.